The field of this invention is heating devices, particularly of the type suitable for jewelry making, electronic assembly and repair, soldering, and the like. Prior art heating devices include those such as disclosed in U.S. Pat. Nos. 3,551,639; 3,662,151; 3,691,342; 3,706,871; 3,716,692; and 3,883,716.
Some of the limitations encountered in these prior art heating devices generally included fixed or limited temperature operation range with no temperature selectivity or adjustment, permanently attached heating elements having one specific temperature range and thus limiting the temperature range of the unit, as well as no provisions for reducing high-frequency electromagnetic radiation typically caused by such heating elements. Still further, most prior art devices failed to provide control switching, such as onoff switching and temperature control of the heating units in the hand-held portion of the unit, but rather required additional remote control boxes to contain the control switching with their associated extra electrical wires and the like. With the additional remote control boxes, precise control of temperature was often difficult to obtain, since the user's attention was divided between the tool and the control box. Further, prior art devices, in part, did not provide for proper thermal insulation of heat sensitive electronic components of the network from the heat generated by the heating element resulting in potential damage to such components. Many of such prior art units further did not include a means for indicating that the unit is on or off and/or indicating the amount of heat being generated adjacent the heating tip. Lastly, none of these devices used multiple insulating sleeves for protecting the user's hand from heat generated by the heating tip under varying temperature situations as well as providing for a compact, easily maneuverable, lightweight, well-balanced, hand-held unit.